Electronic device manufacturers strive to produce a rich interface for users. Conventional devices use visual and auditory cues to provide feedback to a user. In some interface devices, kinesthetic feedback (such as active and resistive feedback) and/or tactile feedback (such as vibration, texture, and heat) is also provided to the user, more generally known collectively as “haptic feedback.” Haptic feedback can provide cues that enhance and simplify the user interface. Specifically, vibration effects, or vibrotactile haptic effects, may be useful in providing cues to users of electronic devices alerting the user to specific events, or in providing realistic feedback to create greater sensory immersion within a simulated or virtual environment.
For example, cell phones are commonly equipped with auditory and visual cues indicating an incoming telephone call. Visual cues typically include flashing lights. Auditory cues typically include a series of tones, synthesized music, or, more recently, digitally-recorded music. However, in some instances, such visual and auditory cues may not be useful to a user of the cell phone. For example, a user in a movie theater will typically have the phone's audible ringer silenced and will have the phone in a pocket and be unable to view the visual cues. In such instances, vibrotactile haptic effects are desirable.
Further, highly configurable and distinctive vibrotactile haptic effects may be desirable. For example, cell phones commonly allow a user to assign specific tones or melodies to identify incoming phone calls from specific numbers. A user may have different audible ring tones for different friends, for work, and for family members. Such differentiation of audible cues allows a user to quickly recognize not only that there is an incoming phone call, but also whom that call is from. However, as described above, in many settings, such differentiation is not possible using standard cell phones. Such phones typically have only a simplistic set of vibrations to indicate an incoming telephone call, but no mechanism for efficiently and effectively generating differentiable vibrotactile haptic effects.